CN103047979B - Passive laser gyroscope - Google Patents

Abstract

The invention discloses a passive laser gyroscope, comprising a laser apparatus, a line-width reduction feedback device and a gyroscope apparatus, wherein the laser apparatus outputs a first laser signal to the line-width reduction feedback device and outputs a second laser signal to the gyroscope apparatus; the line-width reduction feedback device provides the first laser signal to an FP cavity and feeds the laser signal outputted by the FP cavity or an electric signal converted from the laser signal back to the laser apparatus; the laser apparatus locks a central frequency of the first laser signal outputted by the laser apparatus as a resonant frequency of the FP cavity by using the feedback signal; the gyroscope apparatus receives the second laser signal outputted by the laser apparatus; and rotation angular velocity of the gyroscope apparatus is determined by using the line-width reduction laser signal. The central frequency of the laser signal is locked as the resonant frequency of the FP cavity by using a feedback signal mode, so that stability of line-width reduction and the laser frequency of the laser outputted by the laser apparatus can be realized; and precision and sensitivity for measurement of the rotation angular velocity of the laser gyroscope can be increased.

Description

Passive Laser Gyro

technical field

The invention relates to laser technology, in particular to a passive laser gyroscope.

Background technique

As the core inertial device of the inertial navigation system, the gyroscope can be used to measure the small changes in the direction of the aircraft during flight, which helps the inertial navigation system to continuously calculate the position, speed and direction of the aircraft, and realize the aircraft without external reference. Therefore, gyroscopes play a very important role in many fields of national defense science and technology and national economy. Since the invention of laser in the 1960s, research on optical inertial navigation based on the Sagnac effect has developed rapidly. Compared with the traditional mechanical gyroscope, since it does not need to move components during operation, its reliability and resolution have a lot of room for improvement. According to the geometric relationship between the laser gain medium and the ring cavity, the laser gyroscope can be divided into two types: active type and passive type. The active type is when the gain medium is inside the annular cavity, and the passive type is when the gain medium is outside the annular cavity.

The laser gyro determines its rotational angular velocity by measuring the frequency difference between the clockwise (CW) and counterclockwise (CCW) rotations of the laser in the ring cavity. The specific formula is:

$\mathrm{<span\; class="notranslate">\; \&Delta;f</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; A</span>}}{\mathrm{<span\; class="notranslate">\; \&lambda;P</span>}}\mathrm{<span\; class="notranslate">\; \&Omega;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Where Δf represents the measured frequency difference, A is the area surrounded by the ring cavity, λ is the wavelength of the laser, P is the circumference of the area surrounded by the ring cavity, and Ω is the rotational angular velocity of the ring cavity.

In the prior art, in order to improve the sensitivity of angular velocity measurement, attempts have been made to use a ring cavity with the area A as large as possible and a laser wavelength as short as possible. For example, assuming a circular cavity with a frequency resolution of 10 Hz and a wavelength of 0.633 microns, it can be seen from formula (1) that for a gyroscope with a measurement accuracy of 0.001 degrees/s, the corresponding radius of the cavity is 18 mm. If the frequency resolution accuracy is 1000 Hz, the corresponding annular cavity radius is 1.8m. However, increasing the detection sensitivity by increasing the area surrounded by the gyro will bring another problem, that is, with the increase of the area surrounded by the gyro, various unavoidable disturbances will reduce the stability of the gyro.

The noise of the traditional active laser gyroscope mainly comes from two aspects: one is the spontaneous radiation of the laser medium, which is the quantum limit of the noise of the laser gyroscope; , and cause random changes in the phase angle of the output signal. The lockout threshold will affect the linearity and stability of the scale factor of the laser gyroscope. The lock-up threshold depends on the losses in the resonant optical path, mainly the losses of the mirrors.

The passive laser gyroscope can effectively remove the latch-up effect and spontaneous emission noise because the gain medium is outside the ring cavity. Since there is no gain medium in the cavity, the key parameters affecting the accuracy of the laser gyroscope, that is, the stability of the cavity and the line width or fineness of the resonant peak can be further improved. The traditional passive gyroscope can be divided into two ways: the laser is locked on the ring cavity of the gyroscope and the ring cavity of the gyroscope is locked on the laser. However, in the traditional gyroscope, for the former, it is difficult for a general ring cavity, especially a ring cavity with a larger ring area, to effectively suppress external interference, thus reducing the stability of the gyroscope. Therefore, the improvement of the stability of the chamber is technically limited. As for the latter, the line width and stability of ordinary lasers are not very good, which directly limits the accuracy of laser gyroscopes.

Contents of the invention

The technical problem to be solved by the present invention is to provide a passive laser gyroscope, so that the accuracy and sensitivity of the laser gyroscope can be improved.

According to one aspect of the present invention, a passive laser gyro is provided, wherein the laser gyro includes a laser device, a line width narrowing feedback device, a gyro device, and the line width narrowing feedback device also includes a Fabry-Perot The FP cavity, the gyroscopic arrangement also includes an annular cavity, wherein:

The laser device is used to respectively output the first laser signal to the line width narrowing feedback device, output the second laser signal to the gyro device, and use the laser signal or electrical signal fed back by the line width narrowing feedback device to output the second laser signal output by the laser device. The center frequency of the laser signal is locked to the resonant frequency of the FP cavity;

The line width narrowing feedback device is used to provide the first laser signal provided by the laser device to the FP cavity, and feed back the laser signal output by the FP cavity or the electrical signal converted from the laser signal output by the FP cavity for laser devices;

The gyro device is used to receive the second laser signal output by the laser device, and according to the difference between the frequency of clockwise rotation and the frequency of counterclockwise rotation in the ring cavity of the gyro device according to the second laser signal to determine the rotational angular velocity of the gyro device.

In the present invention, the laser signal output by the laser device is fed back to the laser device through the FP cavity, so that the center frequency of the laser signal output by the laser device is locked on the resonant frequency of the FP cavity, and the output of the laser device can be realized by utilizing the stability of the FP cavity. The narrowing of the laser line width and the stability of the laser frequency can improve the accuracy and sensitivity of the laser gyro angular velocity measurement by narrowing the laser line width.

Description of drawings

Fig. 1 is a schematic diagram of an embodiment of the passive laser gyroscope of the present invention.

Fig. 2 is a schematic diagram of an embodiment of the laser device and the line width narrowing device in the laser gyroscope of the present invention.

Fig. 3 is a schematic diagram of another embodiment of the laser device and the line width narrowing device in the laser gyroscope of the present invention.

Fig. 4 is a schematic diagram of an embodiment of the gyro device in the laser gyro of the present invention.

Fig. 5 is a schematic diagram of another embodiment of the gyro device in the laser gyro of the present invention.

Fig. 6 is a schematic diagram of another embodiment of the passive laser gyroscope of the present invention.

Fig. 7 is a schematic diagram of another embodiment of the passive laser gyroscope of the present invention.

Fig. 8 is a schematic diagram of another embodiment of the passive laser gyroscope of the present invention.

Fig. 9 is a schematic diagram of another embodiment of the passive laser gyroscope of the present invention.

Detailed ways

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are illustrated.

Fig. 1 is a schematic diagram of an embodiment of the passive laser gyroscope of the present invention. As shown in Figure 1, the laser gyroscope includes a laser device 1, a line width narrowing feedback device 2, and a gyro device 3. The line width narrowing feedback device 2 also includes a Fabry-Perot FP cavity, and the gyro device 3 also includes includes an annular chamber in which:

The laser device 1 is used to respectively output the first laser signal to the line width narrowing feedback device 2, output the second laser signal to the gyro device 3, and use the laser signal or electrical signal fed back by the line width narrowing feedback device 2 to control the laser device. 1. The center frequency of the output second laser signal is locked to the resonant frequency of the FP cavity;

The line width narrowing feedback device 2 is used to provide the first laser signal provided by the laser device 1 to the FP cavity, and convert the laser signal output by the FP cavity or the electrical signal converted from the laser signal output by the FP cavity The signal is fed back to the laser device 1;

The gyro device 3 is used to receive the second laser signal output by the laser device 1, and to rotate clockwise and counterclockwise in the ring cavity in the gyro device 3 according to the second laser signal. to determine the rotational angular velocity of the gyro device 3 .

Based on the passive laser gyroscope provided by the above-mentioned embodiments of the present invention, the center frequency of the laser signal input by the laser device is locked at At the resonant frequency of the FP cavity, the stability of the FP cavity can be used to narrow the laser linewidth output by the laser device and stabilize the laser frequency, and the accuracy and sensitivity of the laser gyro angular velocity measurement can be improved by narrowing the laser linewidth.

Formula (2) can be obtained by deforming the above formula (1), that is, the expression of angular velocity measurement sensitivity is obtained.

$\mathrm{<span\; class="notranslate">\; \&delta;\&Omega;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&lambda;P</span>}}{\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; A</span>}}\mathrm{<span\; class="notranslate">\; \&delta;\; f</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

where δf is the difference between the frequency at which the laser rotates in the clockwise direction and the frequency at which it rotates in the counterclockwise direction, respectively. It can be seen from formula (2) that under the premise of not modifying the parameters A, λ and P, the angular velocity measurement sensitivity can be improved by reducing the line width of the laser used.

According to a specific embodiment of the laser gyroscope of the present invention, the ring cavity in the gyroscope device can be a fiber ring cavity based on a fiber loop, or a free space ring cavity based on a spatial light.

According to another specific embodiment of the present invention, an FP cavity with high stability can be used, for example, the frequency short-term stability (Allan (Allan) variance) of the laser locked on the FP cavity can be less than or equal to 10 ⁻¹⁰ , preferably , the Allan variance can be less than or equal to 10 ^-11 , 10 ^-12 , 10 ^-13 , 10 ^-14 , 10 ^-15 or 10 ^-16 .

FIG. 2 is a schematic diagram of a specific embodiment of the laser device 1 and the line width narrowing feedback device 2 of the present invention. In the drawings of the present invention, thick lines represent optical paths, and thin lines represent electronic circuits. In FIG. 2 , the laser device 1 includes a laser 101 , an isolator 102 , a first half-wave plate 103 and a first polarization beam splitter prism 104 . The line width narrowing feedback device 2 includes a first electro-optic modulator 201, a first signal source 202, a second polarization beam splitter prism 203, a quarter wave plate 204, a Fabry-Perot (FP) cavity 205, a first A photodetector 206 , a first mixer 207 , and a servo system 208 . Wherein the isolation ratio of the isolator 102 may be greater than 60dB.

Wherein the laser signal output by the laser 101 enters the first polarization beam splitter 104 after passing through the isolator 102 and the first half-wave plate 103, and the first polarization beam splitter prism 104 divides the laser signal into a first laser signal and a second laser signal, The first laser signal is provided to the first electro-optic modulator 201 in the line width narrowing feedback device 2 , and the second laser signal is provided to the gyro device 3 .

After the first electro-optic modulator 201 in the linewidth narrowing feedback device 2 receives the first laser signal, the first electro-optic modulator 201 uses the local oscillator signal provided by the first signal source 202 to process the first laser signal modulation, and the modulated signal is incident into the FP cavity 205 through the second polarization beam splitter prism 203 and the quarter-wave plate 204, wherein the quarter-wave plate 204 is used to change the polarization characteristic of the laser signal from linear polarization to circular Polarization, the light directly reflected in the FP cavity 205 combines and interferes with the light transmitted after oscillation in the FP cavity 205, and the laser signal emitted from the FP cavity 205 passes through the quarter-wave plate 204 again and enters the second polarization beam splitter prism 203. At this time, the quarter-wave plate 204 changes the polarization characteristic of the laser signal into horizontal polarization. After the laser signal is transmitted from the second polarization beam splitter 203, it is received by the first photodetector 206 and converted into an electrical signal. The local oscillator signal generated by the first signal source 202 is mixed in the first mixer 207 and fed back to the laser after passing through the servo system 208 . That is, in this specific embodiment, the signal fed back by the line width narrowing feedback device 2 to the laser device 1 is an electrical signal.

When the line width narrowing feedback device 2 feeds back the electrical signal to the laser device 1, the electrical signal is directly fed back to the laser 101 to lock the center frequency of the laser output from the laser 101 to the resonant frequency of the FP cavity. In this way, the narrowing of the laser line width is realized, and the stability of the FP cavity is transferred to the output frequency of the laser.

According to another specific embodiment of the laser gyroscope of the present invention, in the linewidth narrowing feedback device 2, the electro-optic modulator is usually an electro-optic modulation crystal, which modulates the output frequency of the laser, and the modulation frequency of the electro-optic modulator is f _m1 , by modulating Sidebands of equal size and opposite phase are generated on both sides of the laser center frequency. At the same time, by using sideband frequency locking technology or other corresponding technologies combined with high-speed feedback circuits, the laser frequency can be locked on the resonant frequency of the FP cavity, thereby realizing the narrowing of the laser line width.

According to another specific embodiment of the laser gyroscope of the present invention, the laser may be a distributed feedback laser.

Fig. 3 is a schematic diagram of another embodiment of the laser device and the line width narrowing device of the present invention. In FIG. 3 , the laser device 1 includes a laser 111 , an isolator 112 , a first half-wave plate 113 and a first polarization beam splitter prism 114 . The line width narrowing feedback system 2 includes a Fabry-Perot FP cavity 211 , a fifth total reflection mirror M5 and a sixth total reflection mirror M6 .

The laser signal output by the laser 111 enters the first polarization beam splitter 114 after passing through the isolator 112 and the first half-wave plate 113, and the first polarization beam splitter prism 114 divides the laser signal into a first laser signal and a second laser signal, wherein The first laser signal is provided to the total reflection mirror M5 in the line width narrowing feedback device 2 , and the second laser signal is provided to the gyro device 3 .

The first laser signal enters the FP cavity 211 through total reflection by the total reflection mirror M5 in the line width narrowing feedback device 2 , and the laser signal transmitted from the FP cavity 211 feeds back into the isolator 112 in the laser device 1 through M6 . That is, in this specific embodiment, the signal fed back by the line width narrowing feedback device 2 to the laser device 1 is a laser signal.

When the line width narrowing feedback device 2 provides the feedback laser signal to the isolator 112, the isolator 112 provides the feedback laser signal to the laser 111 to lock the center frequency of the laser output from the laser 111 to the FP cavity resonance frequency.

According to another specific embodiment of the laser gyroscope of the present invention, the laser may be a distributed feedback laser.

Fig. 4 is a schematic diagram of an embodiment of the gyro device in the laser gyro of the present invention. In Fig. 4, the annular cavity in the gyro device is a fiber optic annular cavity.

In Fig. 4, the second laser signal provided by the first polarization beam splitter prism 104 or 114 in the laser device 1 enters the third polarization beam splitter prism 302 through the second half-wave plate 301, and the third polarization beam splitter prism 302 divides the laser signal into The reflection light path and the transmission light path, wherein the reflection light path is divided into a reflection part and a transmission part by the first dichroic prism 303, the reflection part enters the second photodetector 304 for beat frequency measurement, and the transmission part enters the second electro-optic modulator 305, the second The second electro-optic modulator 305 uses the local oscillator signal provided by the second signal source 306 to modulate the transmission part, generates two sidebands on its center frequency side, and performs total reflection on the modulated laser signal through the total reflection mirror M1 After entering the port 1 of the first circulator 307, and exiting from the port 2 of the first circulator 307, it enters the optical fiber ring cavity 309 and rotates in the counterclockwise direction, and the transmitted light of the laser signal rotating in the counterclockwise direction passes through the second ring The port 2 of the device 308 enters the second circulator 308, and enters the second photodetector 310 from the port 3 of the second circulator 308, and the second photodetector 310 converts the laser signal into an electrical signal, and the second mixer 311 mixes the electrical signal converted by the second photodetector 310 with the local oscillator signal generated by the second signal source 306, and then controls the piezoelectric ceramic 313 on the optical fiber ring cavity through the servo system 312. The piezoelectric ceramic 313 is used to realize the The frequency of the local oscillator rotating counterclockwise in the fiber ring cavity is locked to the frequency f ₀ of the laser signal.

At the same time, the transmitted light path provided by the third polarization beam splitter prism 302 passes through the first AOM 314 and the second AOM 315 , and is totally reflected by the total reflection mirrors M2 and M3 respectively. The frequency of the primary light after passing through the first acousto-optic modulator 314 becomes f ₀ +Ω1, and the frequency of the primary light after passing through the second acousto-optic modulator 315 is f ₀ +Ω1-Ω2, where Ω1 and Ω2 are respectively The driving frequency of the AOM 314 and the second AOM 315, the frequency of the zero-order light after passing through the second AOM 315 is f ₀ +Ω1. Wherein the second photodetector 304 combines the laser signal totally reflected by the total reflection mirror M2 with the reflection part provided by the first dichroic prism 303 and provides it to the fourth photodetector 322 to measure the beat frequency. The modulator 316 uses the local oscillator signal generated by the third signal source 319 to modulate the laser signal totally reflected by the total reflection mirror M3, wherein the first-order diffracted light with a frequency of f ₀ +Ω1-Ω2 passes through the third electro-optic modulator 316, Two sidebands are produced on either side of its center frequency. The third electro-optic modulator 316 passes the modulated laser signal into the port 1 of the second circulator 308 through the total reflection mirror M4, enters the optical fiber ring cavity 309 after exiting from the port 2 of the second circulator 308 and rotates clockwise, The transmitted light of the laser signal rotating clockwise enters the first circulator 307 from the port 2 of the first circulator 307, and enters the third photodetector 317 from the port 3 of the first circulator 307, and the third photodetector Converter 317 converts the laser signal into an electrical signal, and the third mixer 318 mixes the electrical signal provided by the third photodetector 317 with the local oscillator signal generated by the third signal source 319 and then controls the voltage controlled oscillator through the servo system 320 321 output frequency Ω1, and provide the output frequency of the voltage controlled oscillator 321 to the first acousto-optic modulator 314. In this way, the frequency of the laser signal is locked to the local oscillator frequency of the laser signal rotating clockwise in the fiber ring cavity.

In the above embodiments, the laser signal is divided into two beams in the gyro device, wherein the resonant frequency of the fiber ring cavity rotating in the counterclockwise direction is locked to the frequency of one of the narrow linewidth laser beams, and the other beam is simultaneously The narrow linewidth laser is locked to the resonant frequency in the fiber ring cavity rotating clockwise. By performing beat frequency processing on the two laser beams, a highly sensitive rotational angular velocity measurement value can be obtained.

Fig. 5 is a schematic diagram of another embodiment of the gyro device in the laser gyro of the present invention. In FIG. 5, the annular cavity in the gyroscopic device is a free space annular cavity.

In Fig. 5, the second laser signal provided by the first polarizing beam splitting prism 104 or 114 in the laser device 1 enters the third polarizing beam splitting prism 402 through the second half-wave plate 401, and the third polarizing beam splitting prism 402 divides the laser signal into The reflection light path and the transmission light path, wherein the reflection light path is divided into a reflection part and a transmission part by the first dichroic prism 403, the reflection part enters the second dichroic prism 404 for beat frequency measurement, the transmission part enters the second electro-optic modulator 405, and the second The electro-optic modulator 405 uses the local oscillator signal provided by the second signal source 406 to modulate the transmitted part, and the modulated laser signal is totally reflected by the total reflection mirror M1, and enters the free space annular cavity through the total reflection mirror M7 420 and rotate in the counterclockwise direction, the transmitted light of the laser signal rotating in the counterclockwise direction exits from M7 and enters the second photodetector 407, the second photodetector 407 converts the laser signal into an electrical signal, and the second mixer 408 The electrical signal converted by the second photodetector 407 is mixed with the local oscillator signal generated by the second signal source 406, and then the piezoelectric ceramic 410 on the free-space annular cavity 420 is controlled by the servo system 409. The piezoelectric ceramic 410 is used to realize the The frequency of the local oscillator rotating counterclockwise in the free-space ring cavity is locked to the frequency _f0 of the laser signal.

At the same time, the transmitted light path provided by the third polarization beam splitter prism 402 passes through the first AOM 411 and the second AOM 412, and is totally reflected by the total reflection mirrors M2 and M3 respectively. The frequency of the primary light after passing through the first acousto-optic modulator 411 becomes f ₀ +Ω1, and the frequency of the primary light after passing through the second acousto-optic modulator 412 is f ₀ +Ω1-Ω2, where Ω1 and Ω2 are respectively The driving frequency of the AOM 411 and the second AOM 412, the frequency of the zero-order light after passing through the second AOM 412 is f ₀ +Ω1. Wherein the second beam splitting prism 404 provides the fourth beam splitting prism 419 to measure the beat frequency after combining the laser signal totally reflected by the total emission mirror M2 and the reflection part provided by the first beam splitting prism 403, and the third electro-optic modulator 413 Utilize the local oscillator signal generated by the third signal source 414 to modulate the laser signal totally reflected by the total reflection mirror M3, wherein the first-order diffracted light with the frequency of f ₀ +Ω1-Ω2 passes through the third electro-optic modulator 413, and at its center Two sidebands are produced on either side of the frequency. The third electro-optic modulator 413 performs total reflection of the modulated laser signal through the total reflection mirror M4, and enters the free space annular cavity 420 through the total reflection mirror M8 and rotates in the clockwise direction, and the transmission of the laser signal rotated in the clockwise direction Light enters the third photodetector 415 from M8, and the third photodetector 415 converts the laser signal into an electric signal, and the third mixer 416 combines the electric signal provided by the third photodetector 415 with the signal generated by the third signal source 414 After the local oscillator signal is mixed, the servo system 417 controls the output frequency of the voltage-controlled oscillator 418 , and provides the output frequency of the voltage-controlled oscillator 418 to the first acousto-optic modulator 411 .

In the above embodiment, the laser signal is divided into two beams in the gyro device, wherein the resonant frequency of the free-space ring cavity rotating counterclockwise is locked to the frequency of one of the narrow linewidth laser beams, while the other A narrow-linewidth laser beam is locked to a resonant frequency rotating in a clockwise direction in a free-space toroidal cavity. By performing beat frequency processing on the two laser beams, a highly sensitive rotational angular velocity measurement value can be obtained.

According to another specific embodiment of the laser gyroscope of the present invention, the line width narrowing feedback system in the laser gyroscope can use the embodiment of the feedback electrical signal as shown in Figure 2, and can also use the implementation of the feedback laser signal as shown in Figure 3 example. At the same time, the gyro device in the laser gyro can use the embodiment using the optical fiber ring cavity as shown in FIG. 4 , or the embodiment using the free space ring cavity as shown in FIG. 5 . For example, Figure 6 shows the embodiment of laser gyroscope using electrical signal feedback and fiber optic ring cavity, Figure 7 shows the embodiment of laser gyroscope using optical signal feedback and fiber ring cavity, and Figure 8 shows the embodiment of laser gyroscope using electrical signal feedback The embodiment of the feedback and the free-space ring cavity, Fig. 9 shows the embodiment of the laser gyroscope adopting the optical signal feedback and the free-space ring cavity.

In the above-mentioned embodiments, due to the use of the line width narrowing technology, the laser line width output by the laser device can reach the order of Hertz, and the line width of the frequency-stabilized He-Ne laser is also in the order of kilohertz. By formula (2) as can be known, the laser gyroscope that the present invention relates to compares with the traditionally used laser gyroscope, under the situation that parameters such as the area that ring cavity surrounds, laser wavelength, the girth of ring cavity surround area are all identical, rotational angular velocity The measurement accuracy can be improved by 2-3 orders of magnitude.

The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and changes will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to better explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention and design various embodiments with various modifications as are suited to the particular use.

Claims (10)

1. A passive laser gyroscope, characterized in that the laser gyroscope comprises a laser device, a line width narrowing feedback device, a gyro device, and a Fabry-Perot FP cavity is included in the line width narrowing feedback device, and the gyro device includes Annulus, in which: The laser device is used to respectively output the first laser signal to the line width narrowing feedback device, output the second laser signal to the gyro device, and use the laser signal or electrical signal fed back by the line width narrowing feedback device to output the second laser signal output by the laser device. The center frequency of the laser signal is locked to the resonant frequency of the FP cavity; The line width narrowing feedback device is used to provide the first laser signal provided by the laser device to the FP cavity, and convert the laser signal output by the FP cavity or the electrical signal converted from the laser signal output by the FP cavity Feedback to the laser device; The gyro device is used to receive the second laser signal output by the laser device, and determine the second laser signal according to the difference between the clockwise rotation frequency and the counterclockwise rotation frequency of the second laser signal in the ring cavity. The rotational angular velocity of the gyroscopic device. 2. The laser gyro according to claim 1, wherein the laser device comprises a laser, an isolator, a first half-wave plate and a first polarization beam splitter, wherein when the line width is narrowed, the feedback device feeds back the laser device When the electrical signal is used, the electrical signal is directly fed back to the laser to lock the center frequency of the laser output laser to the resonant frequency of the FP cavity, and the laser signal output by the laser enters the first polarization after passing through the isolator and the first half-wave plate A beam-splitting prism, the first polarization beam-splitting prism divides the laser signal into a first laser signal and a second laser signal, wherein the first laser signal is provided to the line width narrowing feedback device, and the second laser signal is provided to the gyro device. 3. The laser gyroscope according to claim 2, wherein the line width narrowing feedback device also includes a second polarization beam splitter, a first electro-optic modulator, a first signal source, a quarter wave plate, a first photodetector, first mixer, servo system, wherein: The first polarization beam splitter prism provides the first laser signal to the first electro-optic modulator, and the first electro-optic modulator uses the local oscillator signal provided by the first signal source to modulate the first laser signal, and the modulated The signal enters the FP cavity through the second polarization beamsplitter prism and the quarter-wave plate, where the quarter-wave plate is used to change the polarization characteristic of the laser signal from linear polarization to circular polarization, and the light directly reflected in the FP cavity and the FP After intra-cavity oscillation, the transmitted light combines and interferes, and the laser signal emitted from the FP cavity passes through the quarter-wave plate again and enters the second polarization beam splitter prism, wherein the quarter-wave plate changes the polarization characteristics of the laser signal to For horizontal polarization, the laser signal is received by the first photodetector after being transmitted through the second polarization beam splitter prism and converted into an electrical signal, and the electrical signal is mixed with the local oscillator signal generated by the first signal source in the first mixer, Feedback to the laser after the servo system. 4. The laser gyro according to claim 1, wherein the laser device comprises a laser, an isolator, a first half-wave plate and a first polarization beam splitter, wherein when the line width is narrowed, the feedback device feeds back the laser signal to the laser device , the feedback laser signal is fed back to the isolator, and the isolator provides the feedback laser signal to the laser to lock the center frequency of the laser output laser to the resonant frequency of the FP cavity, and the laser signal output by the laser passes through After the isolator and the first half-wave plate enter the first polarization beam splitter, the first polarization beam splitter divides the laser signal into the first laser signal and the second laser signal, wherein the first laser signal is provided to the line width narrowing The feedback device provides the second laser signal to the gyro device. 5. The laser gyroscope according to claim 4, wherein the line width narrowing feedback device also includes the fifth total reflection mirror and the sixth total reflection mirror, wherein: The first polarization beam splitter prism provides the first laser signal to the fifth total reflection mirror, the first laser signal enters the FP cavity through the total reflection of the fifth total reflection mirror, and the laser signal transmitted from the FP cavity undergoes the sixth total reflection The full feedback of the mirror enters the isolator in the laser setup. 6. The laser gyroscope according to claim 3 or 5, characterized in that the annular cavity in the gyro device is an optical fiber annular cavity or a free space annular cavity. 7. laser gyro according to claim 6, is characterized in that, when the annular cavity in the gyro device is an optical fiber ring cavity, the gyro device comprises a second half-wave plate, a third polarizing beam splitting prism, a first beam splitting prism, a second Dichroic prism, second electro-optic modulator, third electro-optic modulator, first total reflection mirror, second total reflection mirror, third total reflection mirror, fourth total reflection mirror, optical fiber ring cavity, first circulator, second total reflection mirror Two circulators, the second photodetector, the third photodetector, the fourth photodetector, the second mixer, the third mixer, the first acousto-optic modulator, the second acousto-optic modulator, the second Signal source, third signal source, voltage controlled oscillator-, servo, piezoelectric ceramics, wherein: The second laser signal provided by the first polarization beam-splitting prism enters the third polarization beam-splitting prism through the second half-wave plate, and the third polarization beam-splitting prism divides the laser signal into a reflected light path and a transmitted light path, wherein the reflected light path is split by the first beam-splitting prism The reflection part and the transmission part, the reflection part enters the second dichroic prism, and the transmission part enters the second electro-optic modulator, and the second electro-optic modulator uses the local oscillator signal provided by the second signal source to modulate the transmission part, and modulate The final laser signal enters port 1 of the first circulator after being totally reflected by the first total reflection mirror, exits from port 2 of the first circulator, enters the optical fiber ring cavity and rotates counterclockwise, and rotates counterclockwise The transmitted light of the laser signal enters the second circulator from the port 2 of the second circulator, and enters the second photodetector from the port 3 of the second circulator, and the second photodetector converts the laser signal into an electrical signal. The second mixer mixes the electrical signal converted by the second photodetector with the local oscillator signal generated by the second signal source, and then controls the piezoelectric ceramic on the optical fiber ring cavity through the servo system, while the transmitted light path provided by the third polarization beam splitter After passing through the first acousto-optic modulator and the second acousto-optic modulator, total reflection is performed through the second total reflection mirror and the third total reflection mirror respectively, wherein the second dichroic prism totally reflects the laser signal of the second total reflection mirror and The reflected part provided by the first dichroic prism is combined and provided to the fourth photodetector for beat frequency measurement, and the third electro-optic modulator uses the local oscillator signal generated by the third signal source to reflect the total reflection of the third total reflection mirror The laser signal is modulated, and the modulated laser signal enters the port 1 of the second circulator through the fourth total reflection mirror, exits from the port 2 of the second circulator, enters the optical fiber ring cavity and rotates clockwise, along the The transmitted light of the laser signal rotating in the clockwise direction enters the first circulator from port 2 of the first circulator, and enters the third photodetector from port 3 of the first circulator, and the third photodetector converts the laser signal into electrical signal, the third mixer mixes the electrical signal provided by the third photodetector with the local oscillator signal generated by the third signal source, controls the output frequency of the voltage-controlled oscillator through the servo system, and converts the output frequency of the voltage-controlled oscillator to The output frequency is provided to the first acousto-optic modulator. 8. laser gyro according to claim 6, is characterized in that, when the annular cavity in the gyro device is a free space ring cavity, the gyro device comprises a second half-wave plate, a third polarizing beam splitting prism, a first beam splitting prism, The second dichroic prism, the second electro-optic modulator, the third electro-optic modulator, the first total reflection mirror, the second total reflection mirror, the third total reflection mirror, the fourth total reflection mirror, the seventh total reflection mirror, and the eighth total reflection mirror mirror, free space ring cavity, second photodetector, third photodetector, fourth photodetector, second mixer, third mixer, first acousto-optic modulator, second acousto-optic modulator device, second signal source, third signal source, voltage controlled oscillator, servo, piezoelectric ceramics, among which: The second laser signal provided by the first polarization beam-splitting prism enters the third polarization beam-splitting prism through the second half-wave plate, and the third polarization beam-splitting prism divides the laser signal into a reflected light path and a transmitted light path, wherein the reflected light path is split by the first beam-splitting prism The reflection part and the transmission part, the reflection part enters the second dichroic prism, and the transmission part enters the second electro-optic modulator, and the second electro-optic modulator uses the local oscillator signal provided by the second signal source to modulate the transmission part, and modulate The final laser signal is totally reflected by the first total reflection mirror, and enters the free space annular cavity through the seventh total reflection mirror and rotates in the counterclockwise direction, and the transmitted light of the laser signal rotating in the counterclockwise direction passes through the seventh total reflection mirror The output enters the second photodetector, the second photodetector converts the laser signal into an electrical signal, and the second mixer mixes the electrical signal converted by the second photodetector with the local oscillator signal generated by the second signal source and passes through The servo system controls the piezoelectric ceramics on the free-space ring cavity, and at the same time, the transmitted light path provided by the third polarization beam splitter passes through the first AOM and the second AOM, and then passes through the second total reflection mirror and the third total reflection mirror respectively. The reflector performs total reflection, and the second beam splitting prism combines the laser signal totally reflected by the second total reflection mirror with the reflection part provided by the first beam splitting prism and provides it to the fourth photodetector for beat frequency measurement. The three electro-optical modulators use the local oscillator signal generated by the third signal source to modulate the laser signal totally reflected by the third total reflection mirror, and the modulated laser signal is totally reflected by the fourth total reflection mirror, and passed through the eighth total reflection mirror. The mirror enters the free space annular cavity and rotates clockwise, and the transmitted light of the laser signal rotating clockwise enters the third photodetector from the eighth total reflection mirror, and the third photodetector converts the laser signal into an electrical signal , the third mixer mixes the electrical signal provided by the third photodetector with the local oscillator signal generated by the third signal source, and then controls the output frequency of the voltage-controlled oscillator through the servo system, and the output frequency of the voltage-controlled oscillator Provided to the first acousto-optic modulator. 9. The laser gyroscope according to claim 7 or 8, characterized in that, the center frequency of the laser signal output by the laser is f ₀ , the first acousto-optic modulator changes the frequency of the primary light to f ₀ +Ω1, the second The second acousto-optic modulator changes the frequency of the first-order light to f ₀ +Ω1-Ω2, the second acousto-optic modulator changes the frequency of the zero-order light to f ₀ +Ω1, and the output frequency of the voltage-controlled oscillator is controlled to Ω1, Wherein Ω1 and Ω2 are driving frequencies of the first AOM and the second AOM respectively. 10. The laser gyro according to claim 2 or 4, wherein the laser is a distributed feedback laser.